The invention relates to a self-locking belt reel, especially for motor vehicles, with a vehicle-sensitive and/or belt-sensitive control system for the locking member, which in a situation in which the reel needs to be locked prevents further rotation of the belt reeling shaft. It comprises a winding spring acting onto the belt reeling shaft and further comprises a control device which, when the belt is wound onto the reeling shaft provides a release position for the control disc rotating with the belt reeling shaft of the vehicle-sensitive and/or belt-sensitive control system of the belt reel. When the belt has been removed, it secures the control disc against further rotational movement resulting in the blocking of the belt reel.
A belt reel with the aforementioned features is described in German patent 41 32 876 whereby the control device comprises two meshing toothings with respectively arranged switching cams which, at predetermined switching states, engage one another and cause blocking of the control disc. In more detail, a first gear wheel is arranged on the belt reeling shaft which, depending on the switching state, meshes with one of two further gear wheel positioned at the two ends of a pivotably supported rocker on the belt reeling shaft. The three gear wheels each comprise a switching cam whereby two respective switching cams at predetermined removal states will engage one another so that pivoting of the rocker will result from further rotation of the belt reeling shaft upon removal of belt or spring action. The rocker, in turn, moves a switching lever cooperating with the outer toothing of the control disc between a release position and a locking position for the control disc, whereby stopping of the control disc in its rotational movement relative to further rotation of the belt reeling shaft results in pivoting of the locking member and thus locking of the belt reel. In this embodiment of the belt reel, it is achieved that, when a predetermined amount of belt has been removed, the locking system of the belt reel is constantly activated so that each further belt removal results in a locking action of the belt reel while return of the belt and a reverse movement of the belt reeling shaft past the correlated switching position results in a release of the blocking system.
The known belt reel has the disadvantage that for realization of the disclosed control for switching of the belt reel a plurality of components such as rocker, gear wheels, pivotable switching lever, and spring are required whereby their manufacture and mounting is complicated. The invention has the object to simplify for a belt reel having the aforementioned features the control device for switching.